gdhcp/server.c

   1 /*
   2  *
   3  *  DHCP Server library with GLib integration
   4  *
   5  *  Copyright (C) 2009-2012  Intel Corporation. All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <errno.h>
  28 #include <unistd.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <sys/ioctl.h>
  32 #include <arpa/inet.h>
  33
  34 #include <netpacket/packet.h>
  35 #include <net/ethernet.h>
  36 #include <net/if_arp.h>
  37
  38 #include <linux/if.h>
  39 #include <linux/filter.h>
  40
  41 #include <glib.h>
  42
  43 #include "common.h"
  44
  45 /* 8 hours */
  46 #define DEFAULT_DHCP_LEASE_SEC (8*60*60)
  47
  48 /* 5 minutes  */
  49 #define OFFER_TIME (5*60)
  50
  51 struct _GDHCPServer {
  52         int ref_count;
  53         GDHCPType type;
  54         bool started;
  55         int ifindex;
  56         char *interface;
  57         uint32_t start_ip;
  58         uint32_t end_ip;
  59         uint32_t server_nip;    /* our address in network byte order */
  60         uint32_t lease_seconds;
  61         int listener_sockfd;
  62         guint listener_watch;
  63         GIOChannel *listener_channel;
  64         GList *lease_list;
  65         GHashTable *nip_lease_hash;
  66         GHashTable *option_hash; /* Options send to client */
  67         GDHCPSaveLeaseFunc save_lease_func;
  68         GDHCPLeaseAddedCb lease_added_cb;
  69         GDHCPDebugFunc debug_func;
  70         gpointer debug_data;
  71 };
  72
  73 struct dhcp_lease {
  74         time_t expire;
  75         uint32_t lease_nip;
  76         uint8_t lease_mac[ETH_ALEN];
  77 };
  78
  79 static inline void debug(GDHCPServer *server, const char *format, ...)
  80 {
  81         char str[256];
  82         va_list ap;
  83
  84         if (!server->debug_func)
  85                 return;
  86
  87         va_start(ap, format);
  88
  89         if (vsnprintf(str, sizeof(str), format, ap) > 0)
  90                 server->debug_func(str, server->debug_data);
  91
  92         va_end(ap);
  93 }
  94
  95 static struct dhcp_lease *find_lease_by_mac(GDHCPServer *dhcp_server,
  96                                                 const uint8_t *mac)
  97 {
  98         GList *list;
  99
 100         for (list = dhcp_server->lease_list; list; list = list->next) {
 101                 struct dhcp_lease *lease = list->data;
 102
 103                 if (memcmp(lease->lease_mac, mac, ETH_ALEN) == 0)
 104                         return lease;
 105         }
 106
 107         return NULL;
 108 }
 109
 110 static void remove_lease(GDHCPServer *dhcp_server, struct dhcp_lease *lease)
 111 {
 112         dhcp_server->lease_list =
 113                         g_list_remove(dhcp_server->lease_list, lease);
 114
 115         g_hash_table_remove(dhcp_server->nip_lease_hash,
 116                                 GINT_TO_POINTER((int) lease->lease_nip));
 117         g_free(lease);
 118 }
 119
 120 /* Clear the old lease and create the new one */
 121 static int get_lease(GDHCPServer *dhcp_server, uint32_t yiaddr,
 122                                 const uint8_t *mac, struct dhcp_lease **lease)
 123 {
 124         struct dhcp_lease *lease_nip, *lease_mac;
 125
 126         if (yiaddr == 0)
 127                 return -ENXIO;
 128
 129         if (ntohl(yiaddr) < dhcp_server->start_ip)
 130                 return -ENXIO;
 131
 132         if (ntohl(yiaddr) > dhcp_server->end_ip)
 133                 return -ENXIO;
 134
 135         if (memcmp(mac, MAC_BCAST_ADDR, ETH_ALEN) == 0)
 136                 return -ENXIO;
 137
 138         if (memcmp(mac, MAC_ANY_ADDR, ETH_ALEN) == 0)
 139                 return -ENXIO;
 140
 141         lease_mac = find_lease_by_mac(dhcp_server, mac);
 142
 143         lease_nip = g_hash_table_lookup(dhcp_server->nip_lease_hash,
 144                                         GINT_TO_POINTER((int) ntohl(yiaddr)));
 145         debug(dhcp_server, "lease_mac %p lease_nip %p", lease_mac, lease_nip);
 146
 147         if (lease_nip) {
 148                 dhcp_server->lease_list =
 149                                 g_list_remove(dhcp_server->lease_list,
 150                                                                 lease_nip);
 151                 g_hash_table_remove(dhcp_server->nip_lease_hash,
 152                                 GINT_TO_POINTER((int) ntohl(yiaddr)));
 153
 154                 if (!lease_mac)
 155                         *lease = lease_nip;
 156                 else if (lease_nip != lease_mac) {
 157                         remove_lease(dhcp_server, lease_mac);
 158                         *lease = lease_nip;
 159                 } else
 160                         *lease = lease_nip;
 161
 162                 return 0;
 163         }
 164
 165         if (lease_mac) {
 166                 dhcp_server->lease_list =
 167                                 g_list_remove(dhcp_server->lease_list,
 168                                                                 lease_mac);
 169                 g_hash_table_remove(dhcp_server->nip_lease_hash,
 170                                 GINT_TO_POINTER((int) lease_mac->lease_nip));
 171                 *lease = lease_mac;
 172
 173                 return 0;
 174         }
 175
 176         *lease = g_try_new0(struct dhcp_lease, 1);
 177         if (!*lease)
 178                 return -ENOMEM;
 179
 180         return 0;
 181 }
 182
 183 static gint compare_expire(gconstpointer a, gconstpointer b)
 184 {
 185         const struct dhcp_lease *lease1 = a;
 186         const struct dhcp_lease *lease2 = b;
 187
 188         return lease2->expire - lease1->expire;
 189 }
 190
 191 static struct dhcp_lease *add_lease(GDHCPServer *dhcp_server, uint32_t expire,
 192                                         const uint8_t *chaddr, uint32_t yiaddr)
 193 {
 194         struct dhcp_lease *lease = NULL;
 195         int ret;
 196
 197         ret = get_lease(dhcp_server, yiaddr, chaddr, &lease);
 198         if (ret != 0)
 199                 return NULL;
 200
 201         memset(lease, 0, sizeof(*lease));
 202
 203         memcpy(lease->lease_mac, chaddr, ETH_ALEN);
 204         lease->lease_nip = ntohl(yiaddr);
 205
 206         if (expire == 0)
 207                 lease->expire = time(NULL) + dhcp_server->lease_seconds;
 208         else
 209                 lease->expire = expire;
 210
 211         dhcp_server->lease_list = g_list_insert_sorted(dhcp_server->lease_list,
 212                                                         lease, compare_expire);
 213
 214         g_hash_table_insert(dhcp_server->nip_lease_hash,
 215                                 GINT_TO_POINTER((int) lease->lease_nip), lease);
 216
 217         return lease;
 218 }
 219
 220 static struct dhcp_lease *find_lease_by_nip(GDHCPServer *dhcp_server,
 221                                                                 uint32_t nip)
 222 {
 223         return g_hash_table_lookup(dhcp_server->nip_lease_hash,
 224                                                 GINT_TO_POINTER((int) nip));
 225 }
 226
 227 /* Check if the IP is taken; if it is, add it to the lease table */
 228 static bool arp_check(uint32_t nip, const uint8_t *safe_mac)
 229 {
 230         /* TODO: Add ARP checking */
 231         return true;
 232 }
 233
 234 static bool is_expired_lease(struct dhcp_lease *lease)
 235 {
 236         if (lease->expire < time(NULL))
 237                 return true;
 238
 239         return false;
 240 }
 241
 242 static uint32_t find_free_or_expired_nip(GDHCPServer *dhcp_server,
 243                                         const uint8_t *safe_mac)
 244 {
 245         uint32_t ip_addr;
 246         struct dhcp_lease *lease;
 247         GList *list;
 248         ip_addr = dhcp_server->start_ip;
 249         for (; ip_addr <= dhcp_server->end_ip; ip_addr++) {
 250                 /* e.g. 192.168.55.0 */
 251                 if ((ip_addr & 0xff) == 0)
 252                         continue;
 253
 254                 /* e.g. 192.168.55.255 */
 255                 if ((ip_addr & 0xff) == 0xff)
 256                         continue;
 257
 258                 lease = find_lease_by_nip(dhcp_server, ip_addr);
 259                 if (lease)
 260                         continue;
 261
 262                 if (arp_check(htonl(ip_addr), safe_mac))
 263                         return ip_addr;
 264         }
 265
 266         /* The last lease is the oldest one */
 267         list = g_list_last(dhcp_server->lease_list);
 268         if (!list)
 269                 return 0;
 270
 271         lease = list->data;
 272         if (!lease)
 273                 return 0;
 274
 275          if (!is_expired_lease(lease))
 276                 return 0;
 277
 278          if (!arp_check(lease->lease_nip, safe_mac))
 279                 return 0;
 280
 281         return lease->lease_nip;
 282 }
 283
 284 static void lease_set_expire(GDHCPServer *dhcp_server,
 285                         struct dhcp_lease *lease, uint32_t expire)
 286 {
 287         dhcp_server->lease_list = g_list_remove(dhcp_server->lease_list, lease);
 288
 289         lease->expire = expire;
 290
 291         dhcp_server->lease_list = g_list_insert_sorted(dhcp_server->lease_list,
 292                                                         lease, compare_expire);
 293 }
 294
 295 static void destroy_lease_table(GDHCPServer *dhcp_server)
 296 {
 297         GList *list;
 298
 299         g_hash_table_destroy(dhcp_server->nip_lease_hash);
 300
 301         dhcp_server->nip_lease_hash = NULL;
 302
 303         for (list = dhcp_server->lease_list; list; list = list->next) {
 304                 struct dhcp_lease *lease = list->data;
 305
 306                 g_free(lease);
 307         }
 308
 309         g_list_free(dhcp_server->lease_list);
 310
 311         dhcp_server->lease_list = NULL;
 312 }
 313 static uint32_t get_interface_address(int index)
 314 {
 315         struct ifreq ifr;
 316         int sk, err;
 317         struct sockaddr_in *server_ip;
 318         uint32_t ret = 0;
 319
 320         sk = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 321         if (sk < 0) {
 322                 perror("Open socket error");
 323                 return 0;
 324         }
 325
 326         memset(&ifr, 0, sizeof(ifr));
 327         ifr.ifr_ifindex = index;
 328
 329         err = ioctl(sk, SIOCGIFNAME, &ifr);
 330         if (err < 0) {
 331                 perror("Get interface name error");
 332                 goto done;
 333         }
 334
 335         err = ioctl(sk, SIOCGIFADDR, &ifr);
 336         if (err < 0) {
 337                 perror("Get ip address error");
 338                 goto done;
 339         }
 340
 341         server_ip = (struct sockaddr_in *) &ifr.ifr_addr;
 342         ret = server_ip->sin_addr.s_addr;
 343
 344 done:
 345         close(sk);
 346
 347         return ret;
 348 }
 349
 350 GDHCPServer *g_dhcp_server_new(GDHCPType type,
 351                 int ifindex, GDHCPServerError *error)
 352 {
 353         GDHCPServer *dhcp_server = NULL;
 354
 355         if (ifindex < 0) {
 356                 *error = G_DHCP_SERVER_ERROR_INVALID_INDEX;
 357                 return NULL;
 358         }
 359
 360         dhcp_server = g_try_new0(GDHCPServer, 1);
 361         if (!dhcp_server) {
 362                 *error = G_DHCP_SERVER_ERROR_NOMEM;
 363                 return NULL;
 364         }
 365
 366         dhcp_server->interface = get_interface_name(ifindex);
 367         if (!dhcp_server->interface) {
 368                 *error = G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE;
 369                 goto error;
 370         }
 371
 372         if (!interface_is_up(ifindex)) {
 373                 *error = G_DHCP_SERVER_ERROR_INTERFACE_DOWN;
 374                 goto error;
 375         }
 376
 377         dhcp_server->server_nip = get_interface_address(ifindex);
 378         if (dhcp_server->server_nip == 0) {
 379                 *error = G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID;
 380                 goto error;
 381         }
 382
 383         dhcp_server->nip_lease_hash = g_hash_table_new_full(g_direct_hash,
 384                                                 g_direct_equal, NULL, NULL);
 385         dhcp_server->option_hash = g_hash_table_new_full(g_direct_hash,
 386                                                 g_direct_equal, NULL, NULL);
 387
 388         dhcp_server->started = FALSE;
 389
 390         /* All the leases have the same fixed lease time,
 391          * do not support DHCP_LEASE_TIME option from client.
 392          */
 393         dhcp_server->lease_seconds = DEFAULT_DHCP_LEASE_SEC;
 394
 395         dhcp_server->type = type;
 396         dhcp_server->ref_count = 1;
 397         dhcp_server->ifindex = ifindex;
 398         dhcp_server->listener_sockfd = -1;
 399         dhcp_server->listener_watch = -1;
 400         dhcp_server->listener_channel = NULL;
 401         dhcp_server->save_lease_func = NULL;
 402         dhcp_server->debug_func = NULL;
 403         dhcp_server->debug_data = NULL;
 404
 405         *error = G_DHCP_SERVER_ERROR_NONE;
 406
 407         return dhcp_server;
 408
 409 error:
 410         g_free(dhcp_server->interface);
 411         g_free(dhcp_server);
 412         return NULL;
 413 }
 414
 415
 416 static uint8_t check_packet_type(struct dhcp_packet *packet)
 417 {
 418         uint8_t *type;
 419
 420         if (packet->hlen != ETH_ALEN)
 421                 return 0;
 422
 423         if (packet->op != BOOTREQUEST)
 424                 return 0;
 425
 426         type = dhcp_get_option(packet, DHCP_MESSAGE_TYPE);
 427
 428         if (!type)
 429                 return 0;
 430
 431         if (*type < DHCP_MINTYPE)
 432                 return 0;
 433
 434         if (*type > DHCP_MAXTYPE)
 435                 return 0;
 436
 437         return *type;
 438 }
 439
 440 static void init_packet(GDHCPServer *dhcp_server, struct dhcp_packet *packet,
 441                                 struct dhcp_packet *client_packet, char type)
 442 {
 443         /* Sets op, htype, hlen, cookie fields
 444          * and adds DHCP_MESSAGE_TYPE option */
 445         dhcp_init_header(packet, type);
 446
 447         packet->xid = client_packet->xid;
 448         memcpy(packet->chaddr, client_packet->chaddr,
 449                                 sizeof(client_packet->chaddr));
 450         packet->flags = client_packet->flags;
 451         packet->gateway_nip = client_packet->gateway_nip;
 452         packet->ciaddr = client_packet->ciaddr;
 453         dhcp_add_option_uint32(packet, DHCP_SERVER_ID,
 454                                         ntohl(dhcp_server->server_nip));
 455 }
 456
 457 static void add_option(gpointer key, gpointer value, gpointer user_data)
 458 {
 459         const char *option_value = value;
 460         uint8_t option_code = GPOINTER_TO_INT(key);
 461         struct in_addr nip;
 462         struct dhcp_packet *packet = user_data;
 463
 464         if (!option_value)
 465                 return;
 466
 467         switch (option_code) {
 468         case G_DHCP_SUBNET:
 469         case G_DHCP_ROUTER:
 470         case G_DHCP_DNS_SERVER:
 471                 if (inet_aton(option_value, &nip) == 0)
 472                         return;
 473
 474                 dhcp_add_option_uint32(packet, (uint8_t) option_code,
 475                                                         ntohl(nip.s_addr));
 476                 break;
 477         default:
 478                 return;
 479         }
 480 }
 481
 482 static void add_server_options(GDHCPServer *dhcp_server,
 483                                 struct dhcp_packet *packet)
 484 {
 485         g_hash_table_foreach(dhcp_server->option_hash,
 486                                 add_option, packet);
 487 }
 488
 489 static bool check_requested_nip(GDHCPServer *dhcp_server,
 490                                         uint32_t requested_nip)
 491 {
 492         struct dhcp_lease *lease;
 493
 494         if (requested_nip == 0)
 495                 return false;
 496
 497         if (requested_nip < dhcp_server->start_ip)
 498                 return false;
 499
 500         if (requested_nip > dhcp_server->end_ip)
 501                 return false;
 502
 503         lease = find_lease_by_nip(dhcp_server, requested_nip);
 504         if (!lease)
 505                 return true;
 506
 507         if (!is_expired_lease(lease))
 508                 return false;
 509
 510         return true;
 511 }
 512
 513 static void send_packet_to_client(GDHCPServer *dhcp_server,
 514                                 struct dhcp_packet *dhcp_pkt)
 515 {
 516         const uint8_t *chaddr;
 517         uint32_t ciaddr;
 518
 519         if ((dhcp_pkt->flags & htons(BROADCAST_FLAG))
 520                                 || dhcp_pkt->ciaddr == 0) {
 521                 debug(dhcp_server, "Broadcasting packet to client");
 522                 ciaddr = INADDR_BROADCAST;
 523                 chaddr = MAC_BCAST_ADDR;
 524         } else {
 525                 debug(dhcp_server, "Unicasting packet to client ciaddr");
 526                 ciaddr = dhcp_pkt->ciaddr;
 527                 chaddr = dhcp_pkt->chaddr;
 528         }
 529
 530         dhcp_send_raw_packet(dhcp_pkt,
 531                 dhcp_server->server_nip, SERVER_PORT,
 532                 ciaddr, CLIENT_PORT, chaddr,
 533                 dhcp_server->ifindex, false);
 534 }
 535
 536 static void send_offer(GDHCPServer *dhcp_server,
 537                         struct dhcp_packet *client_packet,
 538                                 struct dhcp_lease *lease,
 539                                         uint32_t requested_nip)
 540 {
 541         struct dhcp_packet packet;
 542         struct in_addr addr;
 543
 544         init_packet(dhcp_server, &packet, client_packet, DHCPOFFER);
 545
 546         if (lease)
 547                 packet.yiaddr = htonl(lease->lease_nip);
 548         else if (check_requested_nip(dhcp_server, requested_nip))
 549                 packet.yiaddr = htonl(requested_nip);
 550         else
 551                 packet.yiaddr = htonl(find_free_or_expired_nip(
 552                                         dhcp_server, client_packet->chaddr));
 553
 554         debug(dhcp_server, "find yiaddr %u", packet.yiaddr);
 555
 556         if (!packet.yiaddr) {
 557                 debug(dhcp_server, "Err: Can not found lease and send offer");
 558                 return;
 559         }
 560
 561         lease = add_lease(dhcp_server, OFFER_TIME,
 562                                 packet.chaddr, packet.yiaddr);
 563         if (!lease) {
 564                 debug(dhcp_server,
 565                                 "Err: No free IP addresses. OFFER abandoned");
 566                 return;
 567         }
 568
 569         dhcp_add_option_uint32(&packet, DHCP_LEASE_TIME,
 570                                                 dhcp_server->lease_seconds);
 571         add_server_options(dhcp_server, &packet);
 572
 573         addr.s_addr = packet.yiaddr;
 574
 575         debug(dhcp_server, "Sending OFFER of %s", inet_ntoa(addr));
 576         send_packet_to_client(dhcp_server, &packet);
 577 }
 578
 579 static void save_lease(GDHCPServer *dhcp_server)
 580 {
 581         GList *list;
 582
 583         if (!dhcp_server->save_lease_func)
 584                 return;
 585
 586         for (list = dhcp_server->lease_list; list; list = list->next) {
 587                 struct dhcp_lease *lease = list->data;
 588                 dhcp_server->save_lease_func(lease->lease_mac,
 589                                         lease->lease_nip, lease->expire);
 590         }
 591 }
 592
 593 static void send_ACK(GDHCPServer *dhcp_server,
 594                 struct dhcp_packet *client_packet, uint32_t dest)
 595 {
 596         struct dhcp_packet packet;
 597         uint32_t lease_time_sec;
 598         struct in_addr addr;
 599
 600         init_packet(dhcp_server, &packet, client_packet, DHCPACK);
 601         packet.yiaddr = htonl(dest);
 602
 603         lease_time_sec = dhcp_server->lease_seconds;
 604
 605         dhcp_add_option_uint32(&packet, DHCP_LEASE_TIME, lease_time_sec);
 606
 607         add_server_options(dhcp_server, &packet);
 608
 609         addr.s_addr = htonl(dest);
 610
 611         debug(dhcp_server, "Sending ACK to %s", inet_ntoa(addr));
 612
 613         send_packet_to_client(dhcp_server, &packet);
 614
 615         add_lease(dhcp_server, 0, packet.chaddr, packet.yiaddr);
 616
 617         if (dhcp_server->lease_added_cb)
 618                 dhcp_server->lease_added_cb(packet.chaddr, packet.yiaddr);
 619 }
 620
 621 static void send_NAK(GDHCPServer *dhcp_server,
 622                         struct dhcp_packet *client_packet)
 623 {
 624         struct dhcp_packet packet;
 625
 626         init_packet(dhcp_server, &packet, client_packet, DHCPNAK);
 627
 628         debug(dhcp_server, "Sending NAK");
 629
 630         dhcp_send_raw_packet(&packet,
 631                         dhcp_server->server_nip, SERVER_PORT,
 632                         INADDR_BROADCAST, CLIENT_PORT, MAC_BCAST_ADDR,
 633                         dhcp_server->ifindex, false);
 634 }
 635
 636 static void send_inform(GDHCPServer *dhcp_server,
 637                                 struct dhcp_packet *client_packet)
 638 {
 639         struct dhcp_packet packet;
 640
 641         init_packet(dhcp_server, &packet, client_packet, DHCPACK);
 642         add_server_options(dhcp_server, &packet);
 643         send_packet_to_client(dhcp_server, &packet);
 644 }
 645
 646 static gboolean listener_event(GIOChannel *channel, GIOCondition condition,
 647                                                         gpointer user_data)
 648 {
 649         GDHCPServer *dhcp_server = user_data;
 650         struct dhcp_packet packet;
 651         struct dhcp_lease *lease;
 652         uint32_t requested_nip = 0;
 653         uint8_t type, *server_id_option, *request_ip_option;
 654         int re;
 655
 656         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 657                 dhcp_server->listener_watch = 0;
 658                 return FALSE;
 659         }
 660
 661         re = dhcp_recv_l3_packet(&packet, dhcp_server->listener_sockfd);
 662         if (re < 0)
 663                 return TRUE;
 664
 665         type = check_packet_type(&packet);
 666         if (type == 0)
 667                 return TRUE;
 668
 669         server_id_option = dhcp_get_option(&packet, DHCP_SERVER_ID);
 670         if (server_id_option) {
 671                 uint32_t server_nid =
 672                         get_unaligned((const uint32_t *) server_id_option);
 673
 674                 if (server_nid != dhcp_server->server_nip)
 675                         return TRUE;
 676         }
 677
 678         request_ip_option = dhcp_get_option(&packet, DHCP_REQUESTED_IP);
 679         if (request_ip_option)
 680                 requested_nip = get_be32(request_ip_option);
 681
 682         lease = find_lease_by_mac(dhcp_server, packet.chaddr);
 683
 684         switch (type) {
 685         case DHCPDISCOVER:
 686                 debug(dhcp_server, "Received DISCOVER");
 687
 688                 send_offer(dhcp_server, &packet, lease, requested_nip);
 689                 break;
 690         case DHCPREQUEST:
 691                 debug(dhcp_server, "Received REQUEST NIP %d",
 692                                                         requested_nip);
 693                 if (requested_nip == 0) {
 694                         requested_nip = packet.ciaddr;
 695                         if (requested_nip == 0)
 696                                 break;
 697                 }
 698
 699                 if (lease && requested_nip == lease->lease_nip) {
 700                         debug(dhcp_server, "Sending ACK");
 701                         send_ACK(dhcp_server, &packet,
 702                                 lease->lease_nip);
 703                         break;
 704                 }
 705
 706                 if (server_id_option || !lease) {
 707                         debug(dhcp_server, "Sending NAK");
 708                         send_NAK(dhcp_server, &packet);
 709                 }
 710
 711                 break;
 712         case DHCPDECLINE:
 713                 debug(dhcp_server, "Received DECLINE");
 714
 715                 if (!server_id_option)
 716                         break;
 717
 718                 if (!request_ip_option)
 719                         break;
 720
 721                 if (!lease)
 722                         break;
 723
 724                 if (requested_nip == lease->lease_nip)
 725                         remove_lease(dhcp_server, lease);
 726
 727                 break;
 728         case DHCPRELEASE:
 729                 debug(dhcp_server, "Received RELEASE");
 730
 731                 if (!server_id_option)
 732                         break;
 733
 734                 if (!lease)
 735                         break;
 736
 737                 if (packet.ciaddr == lease->lease_nip)
 738                         lease_set_expire(dhcp_server, lease,
 739                                         time(NULL));
 740                 break;
 741         case DHCPINFORM:
 742                 debug(dhcp_server, "Received INFORM");
 743                 send_inform(dhcp_server, &packet);
 744                 break;
 745         }
 746
 747         return TRUE;
 748 }
 749
 750 /* Caller need to load leases before call it */
 751 int g_dhcp_server_start(GDHCPServer *dhcp_server)
 752 {
 753         GIOChannel *listener_channel;
 754         int listener_sockfd;
 755
 756         if (dhcp_server->started)
 757                 return 0;
 758
 759         listener_sockfd = dhcp_l3_socket(SERVER_PORT,
 760                                         dhcp_server->interface, AF_INET);
 761         if (listener_sockfd < 0)
 762                 return -EIO;
 763
 764         listener_channel = g_io_channel_unix_new(listener_sockfd);
 765         if (!listener_channel) {
 766                 close(listener_sockfd);
 767                 return -EIO;
 768         }
 769
 770         dhcp_server->listener_sockfd = listener_sockfd;
 771         dhcp_server->listener_channel = listener_channel;
 772
 773         g_io_channel_set_close_on_unref(listener_channel, TRUE);
 774         dhcp_server->listener_watch =
 775                         g_io_add_watch_full(listener_channel, G_PRIORITY_HIGH,
 776                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 777                                                 listener_event, dhcp_server,
 778                                                                 NULL);
 779         g_io_channel_unref(dhcp_server->listener_channel);
 780
 781         dhcp_server->started = TRUE;
 782
 783         return 0;
 784 }
 785
 786 int g_dhcp_server_set_option(GDHCPServer *dhcp_server,
 787                 unsigned char option_code, const char *option_value)
 788 {
 789         struct in_addr nip;
 790
 791         if (!option_value)
 792                 return -EINVAL;
 793
 794         debug(dhcp_server, "option_code %d option_value %s",
 795                                         option_code, option_value);
 796         switch (option_code) {
 797         case G_DHCP_SUBNET:
 798         case G_DHCP_ROUTER:
 799         case G_DHCP_DNS_SERVER:
 800                 if (inet_aton(option_value, &nip) == 0)
 801                         return -ENXIO;
 802                 break;
 803         default:
 804                 return -EINVAL;
 805         }
 806
 807         g_hash_table_replace(dhcp_server->option_hash,
 808                         GINT_TO_POINTER((int) option_code),
 809                                         (gpointer) option_value);
 810         return 0;
 811 }
 812
 813 void g_dhcp_server_set_save_lease(GDHCPServer *dhcp_server,
 814                                 GDHCPSaveLeaseFunc func, gpointer user_data)
 815 {
 816         if (!dhcp_server)
 817                 return;
 818
 819         dhcp_server->save_lease_func = func;
 820 }
 821
 822 void g_dhcp_server_set_lease_added_cb(GDHCPServer *dhcp_server,
 823                                                         GDHCPLeaseAddedCb cb)
 824 {
 825         if (!dhcp_server)
 826                 return;
 827
 828         dhcp_server->lease_added_cb = cb;
 829 }
 830
 831 GDHCPServer *g_dhcp_server_ref(GDHCPServer *dhcp_server)
 832 {
 833         if (!dhcp_server)
 834                 return NULL;
 835
 836         __sync_fetch_and_add(&dhcp_server->ref_count, 1);
 837
 838         return dhcp_server;
 839 }
 840
 841 void g_dhcp_server_stop(GDHCPServer *dhcp_server)
 842 {
 843         /* Save leases, before stop; load them before start */
 844         save_lease(dhcp_server);
 845
 846         if (dhcp_server->listener_watch > 0) {
 847                 g_source_remove(dhcp_server->listener_watch);
 848                 dhcp_server->listener_watch = 0;
 849         }
 850
 851         dhcp_server->listener_channel = NULL;
 852
 853         dhcp_server->started = FALSE;
 854 }
 855
 856 void g_dhcp_server_unref(GDHCPServer *dhcp_server)
 857 {
 858         if (!dhcp_server)
 859                 return;
 860
 861         if (__sync_fetch_and_sub(&dhcp_server->ref_count, 1) != 1)
 862                 return;
 863
 864         g_dhcp_server_stop(dhcp_server);
 865
 866         g_hash_table_destroy(dhcp_server->option_hash);
 867
 868         destroy_lease_table(dhcp_server);
 869
 870         g_free(dhcp_server->interface);
 871
 872         g_free(dhcp_server);
 873 }
 874
 875 int g_dhcp_server_set_ip_range(GDHCPServer *dhcp_server,
 876                 const char *start_ip, const char *end_ip)
 877 {
 878         struct in_addr _host_addr;
 879
 880         if (inet_aton(start_ip, &_host_addr) == 0)
 881                 return -ENXIO;
 882
 883         dhcp_server->start_ip = ntohl(_host_addr.s_addr);
 884
 885         if (inet_aton(end_ip, &_host_addr) == 0)
 886                 return -ENXIO;
 887
 888         dhcp_server->end_ip = ntohl(_host_addr.s_addr);
 889
 890         return 0;
 891 }
 892
 893 void g_dhcp_server_set_lease_time(GDHCPServer *dhcp_server,
 894                                         unsigned int lease_time)
 895 {
 896         if (!dhcp_server)
 897                 return;
 898
 899         dhcp_server->lease_seconds = lease_time;
 900 }
 901
 902 void g_dhcp_server_set_debug(GDHCPServer *dhcp_server,
 903                                 GDHCPDebugFunc func, gpointer user_data)
 904 {
 905         if (!dhcp_server)
 906                 return;
 907
 908         dhcp_server->debug_func = func;
 909         dhcp_server->debug_data = user_data;
 910 }